Just spent some time trying to research the potential environmental impact of the most visible spectacle of the United States Thanksgiving Day celebration in New York City, the annual Macy's parade.

I suppose I could add up the fuel used to move the planned 58 helium balloons and 27 floats down more than two miles of Manhattan streets. Then factor in what it takes to transport the anticipated crowd of 8,000 participants and 3.5 million watchers into the downtown area. The 12 bands that march the route are obviously walking, so good for them. The biggest concern, apparently, is the roughly 300,000 cubic feet of helium used to fill the balloons, which is evidently an increasingly rare gas. A couple of years ago, Macy's worked with a company to recycle the helium afterwards, but I haven't seen any news on that for this year.

It takes part in a program called the Empty Miles Service, which helps coordinate shipping and carriers to cut down on the practice of sending empty trucks

And, this a big one: the retailer uses recycled or certified sustainable paper for 63 percent of its marketing materials and up to 82 percent in its shopping bags.

Looking forward, Macy's has set some new sustainability goals that prove it isn't just in this for the short term. Over the next three years, for example, it seeks to reduce its energy consumption on a kilowatt-hour-per-square-foot basis by another 8 percent to 10 percent over 2009 levels. It will install between 15 percent to 25 percent more of renewable energy capacity during that same timeframe. And, it plans to cut its paper consumption by 10 percent by 2013 (over 2009), while increasing the amount of recycled paper in its marketing materials to 70 percent (from the 63 percent stated above).

To be fair, there are other retailers that have made a bigger impact than Macy's in one area in particular, the use of green power, which is defined by the U.S. Environmental Protection Agency as electricity generated from renewable sources such as wind, solar, geothermal, certain times of hydro, and biomass.

Here are the Top 20 Retail Companies on the EPA's Green Power Partnership list, along with the percentage of their electricity generated by green power sources. In some cases, the percentage may seem small, but consider that those companies consume more electricity than others listed above them on the list. The electricity could come in the form of actual generating capacity or renewable certificates.

Remember these companies when you get ready to plunk down some money on Black Friday.